One of Britain's leading archaeologists, Lord Renfrew, yesterday demanded that the government and the British art trade act urgently to end the "sickening enterprise" of trade in looted antiquities.

A report published yesterday by the Museums Association and the International Council of Museums suggested that the British end may be worth £50m a year, of an international trade worth billions.

The report describes the trade as "the theft of history", and outlines the increasing involvement of criminals and drug barons; sites in Africa, the far east and South America being pillaged to order for collectors; and the injuries and deaths of museum staff, particularly in Africa, where looters are targeting existing collections.

It suggests London sales may be used as a laundering exercise, to give looted objects a saleroom history before they are sold on again.

"I hope this may be a turning point in a major scandal nationally and internationally," Lord Renfrew, professor of archaeology at Cambridge, said. He has been appointed to an advisory committee, established last month by the Department of Culture, to report by autumn on how to tackle the trade.

However yesterday he denounced this and previous governments for decades of inaction, and for repeatedly refusing to sign UN and other protocols outlawing the trade.

It is not illegal to sell antiquities in Britain, even if they have been illegally excavated and exported from elsewhere. Sotheby's has recently dropped its antiquities auctions in London, though it still sells them in New York, but other leading London auction houses, including Bonham's, still hold regular sales of archaeological finds.

In some countries, such as Cambodia, massive sculptures are being hacked off sites of world importance and sold in art galleries. In others, archaeology sites are being scoured bare of small, portable, readily saleable and virtually untraceable objects.

Archaeologists are in despair over the trade because in stripping the objects of their context, the looters destroy the wealth of information which they might reveal of the cultures which made them.

Many of the most notorious cases concern Africa and the far east, but British sites are also being targeted: Wanborough in Guildford became notorious in the 1980s, when gangs of treasure hunters came by night with metal detectors and removed sack loads of Roman coins, mostly since sold abroad.

Two years ago, after reports that treasure hunters has returned, archaeologists carried out an emergency excavation to learn what they could about the site - which may have been of importance to pagans then re-used as a Roman temple.

Tony Robinson, presenter of the Channel 4's archaeology series Time Team, said: "To rip archaeology out of the earth is an attack not just on us but on our children too."

He said in touring the country for the series he had come across innumerable stories of landowners calling in the police to deal with unauthorised metal detectorists, only to find the police or magistrates interested or even amused by what they saw as a harmless hobby.